There is important documentation of Daniels' mathematical studies at Edinburgh and Cambridge in the form of student notebooks. There are thirteen notebooks which appear to have been used by Daniels at Edinburgh for lecture notes. Members of the academic staff of the University represented by lecture notes include the head of department, E.T. Whittaker, C.G. Darwin, Tait Professor of Natural Philosophy, W.H. McCrea and A. Oppenheimer. As many as twenty notebooks appear to have been used at Cambridge. Members of the academic staff represented include A.S. Eddington, Plumian Professor of Astronomy and mathematics lecturers A.E. Ingham, M.H.A. Newman and A.H. Wilson. Agricultural statistics are represented by notes of H.G. Sanders' lectures on field experimentation with practical examples. There are a small number of caricature sketches (heads in profile) of Daniels' lecturers in the student notebooks and Eddington is one of those represented in this way. There are a further six notebooks which do not appear to be student notebooks though only one is dated 'Lent 1950' when Daniels was a mathematics lecturer at Cambridge.
Research material is presented in an alphabetical sequence by folder or box title. The principal contents of Daniels' research folders are sequences of undated manuscript notes, only occasionally titled but often paginated and kept together with treasury tags; data, in manuscript form or automatically generated; and off-prints and photocopies of published material. Additionally there may be notes in hands other than Daniels' and a little correspondence. Topics include 'bundles' and epidemics and a number of Daniels' folders were identified with the names of colleagues including D.J. Bartholomew and D.R. Cox.
The earliest surviving material relates to the wartime work on navigational problems and postwar Decca Navigator System papers, which were sent to Daniels in 1947, probably relate to this work.
There is extensive material relating to Daniels' lectures and publications. There is a significant record of Daniels' university teaching at Cambridge and Birmingham arranged alphabetically by folder title. Course topics include Design of Experiments, Epidemics, Mechanics and Multivariate Analysis. The documentation may include Daniels' manuscript lecture notes, lists of students taking the courses, examples and problem sheets, and related material from colleagues. Daniels' annotation of his lecture notes gives some indication of how lecture courses were adapted over time. There is a shorter sequence of lecture course material arranged alphabetically by colleague. Amongst those represented are F.J. Anscombe, M.S. Bartlett, E.L. Lehmann and D. Williams. There is a good record of Daniels' seminar and conference papers for the last ten years of his life, 1990-2000. The documentation is principally transparencies and manuscript notes. For conferences in Uppsala, Sweden, in 1990 and Ascona, Switzerland, in 1995 and 2000 there is also correspondence arranging Daniels' participation in the meeting. Daniels' publications are represented by his bibliography and a good set of off-prints, 1932-2000.
Daniels' correspondence is not extensive. It is predominantly the contents of a single folder, covering the period 1992-1999. The correspondence is largely scientific and includes photocopies and manuscript drafts of Daniels' replies.